McCormick Gail L, Langkilde Tracy
Intercollege Graduate Degree Program in Ecology, Department of Biology, and The Center for Brain, Behavior and Cognition, The Pennsylvania State University, 208 Mueller Laboratory, University Park, PA 16802, USA.
Intercollege Graduate Degree Program in Ecology, Department of Biology, and The Center for Brain, Behavior and Cognition, The Pennsylvania State University, 208 Mueller Laboratory, University Park, PA 16802, USA.
Gen Comp Endocrinol. 2014 Aug 1;204:135-40. doi: 10.1016/j.ygcen.2014.04.037. Epub 2014 May 20.
Prolonged elevations of glucocorticoids due to long-duration (chronic) stress can suppress immune function. It is unclear, however, how natural stressors that result in repeated short-duration (acute) stress, such as frequent agonistic social encounters or predator attacks, fit into our current understanding of the immune consequences of stress. Since these types of stressors may activate the immune system due to increased risk of injury, immune suppression may be reduced at sites where individuals are repeatedly exposed to potentially damaging stressors. We tested whether repeated acute elevation of corticosterone (CORT, a glucocorticoid) suppresses immune function in eastern fence lizards (Sceloporus undulatus), and whether this effect varies between lizards from high-stress (high baseline CORT, invaded by predatory fire ants) and low-stress (low baseline CORT, uninvaded) sites. Lizards treated daily with exogenous CORT showed higher hemagglutination of novel proteins by their plasma (a test of constitutive humoral immunity) than control lizards, a pattern that was consistent across sites. There was no significant effect of CORT treatment on bacterial killing ability of plasma. These results suggest that repeated elevations of CORT, which are common in nature, produce immune effects more typical of those expected at the acute end of the acute-chronic spectrum and provide no evidence of modulated consequences of elevated CORT in animals from high-stress sites.
由于长期（慢性）应激导致糖皮质激素长期升高会抑制免疫功能。然而，目前尚不清楚诸如频繁的竞争性社会交往或捕食者攻击等导致反复短期（急性）应激的自然应激源如何与我们目前对压力免疫后果的理解相契合。由于这些类型的应激源可能因受伤风险增加而激活免疫系统，在个体反复暴露于潜在有害应激源的部位，免疫抑制可能会降低。我们测试了反复急性升高皮质酮（CORT，一种糖皮质激素）是否会抑制东部围栏蜥蜴（Sceloporus undulatus）的免疫功能，以及这种影响在来自高应激（高基线CORT，被捕食性火蚁入侵）和低应激（低基线CORT，未被入侵）地点的蜥蜴之间是否存在差异。每天接受外源性CORT治疗的蜥蜴血浆对新蛋白质的血凝反应（一种组成性体液免疫测试）高于对照蜥蜴，这种模式在不同地点都是一致的。CORT治疗对血浆的细菌杀伤能力没有显著影响。这些结果表明，自然界中常见的CORT反复升高产生的免疫效应更符合急性-慢性应激谱急性端预期的典型效应，并且没有证据表明来自高应激地点的动物CORT升高会产生调节性后果。
